[HOU-3976] [HOU-3977] HOUDINI GPU TRIPLANAR REST issue

[sami_tawil]

Hello,

I have been scanning the forum and couldn't find something that works for me.
I have a delayed load alembic with rest attribute, i am using a triplanar texture and the rest attribute isn't working with gpu.
I have no issue with the cpu, it works as intended

thank you for your help

[sami_tawil]

The only way i can make it work with gpu, is using completely unpacking them, which defies the purpose

[tsvetomira.girginova]

Dear sami_tawil, hello.

Could you please confirm that the described by you is similar to the discussion here?

Yes, we have encountered differences when using GPU and the issue is partly solved - alembic files are still on the list to be fixed.
Will add this forum thread to the report and inform you when a build including a fix is available for testing.

Best regards,
TS

[sami_tawil]

my issue is that the texture slide when using alembic delayed load with triplanar on GPU with rest attribute
This issue doesn't occur when i use CPU with the same set up.
For the gpu to have "sticky" texture using rest, i need to unpack my alembic inside houdini


Thank you

[tsvetomira.girginova]

Thanks!

At the moment this is the way of work on GPU.
The alembic support should be separately implemented. Unfortunately it will take some time and we are not able to share certain time frame.

You will be informed when it is done.

[gagui]

I can confirm this happends on regular geometry made directly in houdini aswell.
In cpu works as expected but in GPU the triplanar projection slides.

I've added a rest node before transformation and activated the rest paramenter in object properties, in gpu the texture slides.

I've even tried to plug a vray user color with rest attribute connected to triplanar node. In this case the texture seems to stick to surface but the projection in certain angles is wrong.

I attach a test scene to see the problem.

[tsvetomira.girginova]

Dear gagui, hello.

Thank you for the provided scene.
After exploring the options and the implemented changes, I can now confirm that V-Ray GPU is working fine in CUDA mode, but unfortunately when RTX is used - the issue is visible.
Our devs will take a look and I will inform you by any change.

Best regards,
TS

[gagui]

Hi!

After your last info I've been testing CUDA mode and I still found some inconsistencies compared to CPU mode.
In general seems to work well but I have some imported FBX geometry that does some weird things in CUDA mode that none of CPU or RTX does. I attach couple of images to illustrate this.
This geometry is cleaned and only have P and rest attibutes.

Test scene attached aswell.

[tsvetomira.girginova]

Hi again, gagui !

I tested your scene with one of our latest nightly builds (22482) and with GPU driver version 531.41.
The results are not the same and the differences are smaller between CPU and CUDA, see here:


We are working on some improvements now, so I will continue testing next week with the newer builds too.
Enjoy the weekend!

[gagui]

Hello.

I've installed last nightly build but I'm still getting some weird results.
My nvidia drivers are 536.99.

[tsvetomira.girginova]

Dear gagui, hello again.

These are my recent results with the same Houdini version, NVIDIA driver version 536.40 (currently recommended one listed here) and nightly build 22495 from September 03:
As far as I see a difference stands in the existing Redshift installation (Redshift OBJ properties are added to the object). On my side they are per default and not applied.
Another one is the NVIDIA driver version.

I was able to produce equal results with RTX if no rotation is applied via transform, so will list this one to our bug tracking system for improvement.
If you are able to use same driver version, same nightly build and disable Redshift OBJ properties, are you receiving the same results?
Otherwise the key is hidden somewhere else and we need to continue the investigation.

Waiting for your answer.

[gagui]

Hi Tsvetomira.

I've tested last nightly build and found that CUDA renders fine but only with production render. If I do an IPR with CUDA the texture still look like this:



RTX still doesn´t take transformations ok as we can see in your screencap.

[tsvetomira.girginova]

Thank you!
Reproduced.